Spray for coating molds



Patented May 2, 1933 seen an new,

PATENT OFFICE JAMES F. MCGLINTIC, OF DETROIT, MICHIGAN, ASSIGNOR TO GENERAL MOTORS RESEARCH CORPORATION, OF DETROIT, MICHIGAN, A CORPORATION OF DELA- WARE No Drawing.

The object of this invention is to provide a against the erosive efiects of the molten metal 'face's of gre cast therein. 5, When molten metal is cast directly onto the surface of a green sand mold, the molten metal burns into the sand and a rough-sur-' faced casting, which is hard to clean, is produced. To the end of producing castings 10, having smooth surfaces, it has become the common practice to face the surfaces of green sand molds, which are to be exposed to the erosive effects of the molten metal, with a mixture of sea coal and molding sand to i prevent the mbl'teimetal from burning into the green sand. Although this practice has, to some extent, attained the desired objects, it has not been entirely successful and is more or less expensive-and difficult to carry out successfully.

I have discovered that if a finely powdered refractory is suspended in asuitable drying liquid or binder, which has been diluted to a suitable consistency with a rather highly volatile liquid, a mixture is produced which may be applied to the surface of a mold with a spray gun or atomizer. On account of the rapid rate at which the diluent evaporates, which may be accelerated by spraying the mixture on the mold while the latter is in a heated condition, there is practically no tendency for the mixture to run and the surface of the mold consequently becomes covered with a uniformly thick coating of finely divided partcles of refractory bound together by the drying liquid. To hasten Qgglrying SPRAY FOR COATING MOLDS Application filed. May 31, 1929. Serial No. 367,630.

of gasoline is an eminently satisfactory spray coating for protecting the surfaces of molds for applying a p r-otect iyefoaftfifiggs'tjfi 'fl jg andmolds The proportions artnssevsral ingredients may, of course, be varied to suit various conditions. The spray may be applied directly to the surface of the green sand mold or may be applied to the surface of a coating of a mixture of sea coal and molding sand, which has previously been applied thereto. In the latter case, it is not necessary to use as thick a coating of the mixture of sea coal and molding sand as would otherwise be necessary.

Although the spray has been described with reference to its use in connection with green sand molds, it is to be understood that it may, with equal facility and effectiveness, be used in connection with permanent molds or dry sand molds.

I claim:

1. A spray for molds, which consists of four (4) parts, by volume, of finely powd- 1 ered plumbago suspended in a mixture of two 1 (2) parts, by volume, of core oil and two (2) parts, by volume, of gasoline.

2. A double coating for sand molds consisting of a layer of sea coal adhering to the mold surface and a superposed layer of i powdered plumbago mixed with heavy oil and a highly volatile hydro carbon.

3. A coating for molds, which consists of a layer of sea coal adhering to the surface of the mold and a layer of plumbago and core oil superimposed on the layer of sea coal.

4. A preparation for coating molds which consist of plumbago, core oil and gasoline.

of the coating, the mold may bg haatediinmam In testimony whereof I atfix my signature.

contains, in addition to'the linseed oil, other n active or inert ingredients such as rosin oil and kerosene, and two (2) parts, byvolunif JAMES F. MoCLINTIO. 

